RSTP Diagnostics

Introduction

Use the RSTP Diagnostic page to view the status of the RSTP service of the embedded Ethernet scanner service in the CPU. The page displays dynamically generated and static data for the module.

NOTE: Before you can open the diagnostics page, make the connection between the DTM for the CPU’s embedded scanner service and the physical module.

Open the Page

Access the RSTP Diagnosis information:

Step	Action
1	In the DTM Browser, right-click the name that is assigned to your CPU.
2	Select Device menu > Diagnosis.
3	In the left pane of the Diagnosis window, select the CPU node.
4	Select RSTP Diagnostic tab to open that page.

Data Display

Select the Refresh Every 500ms check box to display the static or dynamic data:

Checkbox	Description
Selected	Display data that is dynamically updated every 500 ms. Increment the number at the top of the table each time data is refreshed.
De-selected	Display static data. Do not increment the number at the top of the table. That number now represents a constant value.

RSTP Diagnostic Parameters

The RSTP Diagnostic page displays the following parameters for each CPU port:

Parameter	Description
Bridge RSTP Diagnostic:
Bridge Priority	This 8-byte field contains the two-byte value that is assigned to the CPU’s embedded Ethernet switch.
MAC Address	The Ethernet address of the CPU, found on the front of the CPU.
Designated Root ID	The Bridge ID of the root device.
Root Path Cost	The aggregate cost of port costs from this switch back to the root device.
Default Hello Time	The interval at which Configuration BPDU messages are transmitted during a network convergence. For RSTP this is a fixed value of 2 seconds.
Learned Hello Time	The current Hello Time value learned from the root switch.
Configured Max Age	The value (6 ... 40) that other switches use for MaxAge when this switch is acting as the root.
Learned Max Age	The maximum age learned from the root switch. This is the actual value currently used by this switch.
Total Topology Changes	The total number of topology changes detected by this switch since the management entity was last reset or initialized.
Ports ETH 2 and ETH 3 RSTP Statistics:
Status	The port's current state as defined by RSTP protocol. This state controls the action the port takes when it receives a frame. Possible values are: disabled, discarding, learning, forwarding.
Role:	The port’s current role per RSTP protocol. Possible values are: root port, designated port, alternate port, backup port, disabled port.
Cost	The logical cost of this port as a path to the root switch. If this port is configured for AUTO then the cost is determined based on the connection speed of the port.
STP Packets	A value in this field indicates that a device on the network has the STP protocol enabled. NOTE: Other devices that are enabled for STP can severely affect the network convergence times. Schneider Electric recommends that you disable the STP protocol (but not the RSTP protocol) on every network device that supports STP. The CPU does not support the STP protocol. The CPU’s embedded switch ignores STP packets.